60 DAIRY CHEMISTRY 



portant as the use of good yeast in bread making. 

 The milk from a fresh and perfectly healthy cow 

 should be used in preparing the starter, rather than 

 the mixed milk of an entire herd. In the prepara- 

 tion and use of the culture, scrupulous cleanliness 

 should be practiced. A number of commercial cul- 

 tures for the ripening of cream have been placed on 

 the market, as Conn's bacillus N.o. 41 and Hanson's 

 lactic ferment. In the use of these, or of home- 

 made cultures, good results cannot be secured unless 

 the cream is cared for and manipulated in the 

 proper way. The best quality of butter cannot be 

 made from cream that has been contaminated in any 

 way or contains abnormal ferment bodies. 



63. Influence of Delay on the Creaming of Milk. — 

 When milk is creamed by the centrifugal method, 

 there is no loss of efficiency in creaming if the milk 

 is not separated at once, provided the proper tem- 

 perature is secured when the milk is separated. 

 When milk is creamed by the cold deep setting pro- 

 cess, unnecessary delay should be avoided, but undue 

 haste in placing the milk in the tank water is not 

 necessary. However^ the milk should not be left in 

 the barn. Experiments at the Maine and Cornell, 

 Experiment Stations have shown that with the 

 mixed milk of an entire herd there is no appreciable 

 loss of fat when the placing of the milk in the tank 

 has been delayed for half or three quarters of an 

 hour. At the Wisconsin Station experiments showed 

 that with three lots of cows there was no loss in 



